Oil and gas reservoir water invasion inhibitor and application thereof

Abstract

The invention provides an oil and gas reservoir water invasion inhibitor and application thereof. The oil and gas reservoir water invasion inhibitor comprises a modification treatment agent, nano silicon dioxide and alcohol, and has temperature resistance and salt resistance.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, and in particular to a water intrusion inhibitor for oil and gas reservoirs and its application. Background Technology

[0002] During oil and gas extraction, the continuous injection of large amounts of water-based working fluid pushes gas deeper into the reservoir, causing severe water intrusion damage. Due to capillary effects, formation pressure cannot completely expel the stagnant fluid, leading to increased water saturation and decreased gas phase permeability. To allow the gas phase to carry the water phase towards the wellbore, this capillary resistance and fluid flow friction must be overcome—the so-called "water lock." Water lock damage can lead to reduced or even halted gas well production, severely impacting the production and operation of oil and gas reservoirs.

[0003] Existing technologies primarily reduce the surface tension of the aqueous phase in gas wells, transforming the oil and gas reservoir from strongly hydrophilic to weakly hydrophilic, thereby reducing capillary resistance in the gas-liquid two-phase system. However, for low-permeability reservoirs, as the gas well production time increases, the reservoir pressure further decreases, and water-locking damage persists, making it difficult for reservoir water to drain from the wellbore.

[0004] How to modify oil and gas reservoirs to be superwettable (superhydrophobic) in order to achieve the dual goals of relieving water lock and preventing water intrusion is a problem that urgently needs to be solved in this field. Summary of the Invention

[0005] One of the present inventions provides a water intrusion inhibitor for oil and gas reservoirs, which comprises a modifier, nano-silica, and an alcohol.

[0006] In one specific embodiment, the modifying agent includes a fluorocarbon surfactant and a hydrophilic siloxane coupling agent.

[0007] In one embodiment, the fluorocarbon surfactant comprises perfluorooctyl sulfonamide and / or tetraethylammonium perfluorooctyl sulfonate.

[0008] In one specific embodiment, the hydrophilic siloxane coupling agent includes at least one of perfluorooctylsulfonamide propylamine oxide, 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane, palmitoyl chloride as a modifier, and triethylamine as an acid binder.

[0009] In one specific embodiment, the mass ratio of the fluorocarbon surfactant to the hydrophilic siloxane coupling agent is (1.4-1.7):1.

[0010] In one specific embodiment, the alcohol is methanol and / or ethanol.

[0011] In one specific embodiment, the alcohol is a mixture of methanol and ethanol in a volume ratio of 1:1.

[0012] In one specific embodiment, the nano-silica is hydrophilic nano-silica.

[0013] In one specific embodiment, the content of the modifying agent is 1% to 3% based on the total mass of the inhibitor (100%), and the content of the nano-silica is 0.1% to 0.5%.

[0014] In one specific embodiment, the content of the modifying agent is 2% to 2.5% based on the total mass of the inhibitor (100%), and the content of the nano-silica is 0.1% to 0.3%.

[0015] The second aspect of the present invention provides the application of the inhibitor according to any one of the present invention in water intrusion in oil and gas reservoirs.

[0016] In one specific embodiment, this is particularly applied to suppress water intrusion in high-temperature, high-salinity oil and gas reservoirs. The high temperature reaches a maximum of 180°C; the high salinity reaches a maximum of 250,000 mg / L.

[0017] The beneficial effects of this invention are:

[0018] (1) The reservoir water intrusion inhibitor of the present invention can reduce the surface tension of near-wellbore fluids, change the wettability of sandstone surfaces, superhydrophobically modify the sandstone surface, increase the contact angle between the aqueous phase and the sandstone surface, and reduce the capillary resistance of the fluid. The water intrusion inhibitor is more firmly adsorbed onto the sandstone surface, is less likely to be washed away, has a longer effective period, and the free radicals exposed in the solution provide conditions for the introduction of the modifier, combining the sandstone surface with the modifier to complete the modification work of reducing the surface energy of the sandstone. Because the long alkyl chain of the modifier is exposed on the sandstone surface, the sandstone surface is modified into a superhydrophobic surface.

[0019] (2) The nano-SiO2 in the reservoir water intrusion inhibitor of this invention exhibits a synergistic effect with the modification agent (fluorocarbon surfactant and hydrophilic siloxane coupling agent). According to the Wenzel equation, the rock surface becomes more hydrophobic as the surface roughness increases. Based on the superhydrophobic modification component covering the rock surface, nano-SiO2 and micron-sized pores form a micro-nano dual-scale rough structure, thereby achieving a superhydrophobic effect on the rock surface. This greatly reduces the adhesion resistance of fluids on the sandstone surface, effectively improves the flow capacity of fluids in porous media, thereby restoring the formation permeability and allowing formation fluids to seep better into the wellbore.

[0020] (3) The reservoir water intrusion inhibitor of the present invention has low surface tension, which is conducive to water backflow. It shows no discoloration, stratification, or precipitation in 250,000 mg / L NaCl brine, exhibiting excellent salt tolerance. After aging at 180℃ for 48 hours, the surface tension of the water intrusion inhibitor remains essentially unchanged, and the contact angle of the core surface treated with the water intrusion inhibitor also remains essentially unchanged. Therefore, the reservoir water intrusion inhibitor of the present invention has excellent temperature and salt tolerance, making it suitable for high-temperature, high-salinity oil and gas reservoirs.

[0021] (4) The raw materials of the oil and gas reservoir water invasion inhibitor of the present invention can all be purchased from the market, are inexpensive, and are easy to prepare and can be mass-produced industrially.

[0022] (5) The present invention is a uniform aqueous dispersion system, which can greatly avoid the problem of poor injection performance of polymer and emulsion systems in reservoirs. Attached Figure Description

[0023] Figure 1 The contact angle test results of Example 1 are shown.

[0024] Figure 2 The contact angle test results of Example 2 are shown.

[0025] Figure 3 The contact angle test results of Example 3 are shown.

[0026] Figure 4 The contact angle test results of Example 4 are shown.

[0027] Figure 5 The contact angle test results of Example 5 are shown.

[0028] Figure 6 The contact angle test results of Example 6 are shown.

[0029] Figure 7 The contact angle test results of Example 7 are shown.

[0030] Figure 8 The contact angle test results of Example 8 are shown. Detailed Implementation

[0031] The present invention will be further described below with reference to the embodiments. However, the embodiments of the present invention are merely illustrative examples and should not be construed as limiting the present invention under any circumstances.

[0032] To evaluate the performance of the reservoir water intrusion inhibitor of this invention, it was applied in a laboratory using artificial quartz sandstone cores. These cores were artificially cemented, with an initial permeability of approximately 5 to 30 mD and a porosity of 8% to 10%.

[0033] The process of hydrophobic modification of sandstone surface: Dry the core, then soak it in water erosion inhibitor at 60℃ to 80℃ for 24 hours, and air dry it to obtain superhydrophobic surface core.

[0034] Contact angle determination: The gas-liquid-solid three-phase contact angle of the droplet on the core surface treated with reservoir water intrusion inhibitor was determined using the lying drop method. The specific operation is as follows: The core was cleaned with ethanol, then immersed in reservoir water intrusion inhibitor, treated at 80℃ for 24 hours, and then air-dried at room temperature to obtain a superhydrophobic core. The superhydrophobic core was then coated onto a glass surface using a spin-coating method, and its gas-liquid-solid three-phase contact angle was measured using an εrma angle meter contact angle meter (Kyowa Corporation, Japan, G-1 type).

[0035] Surface tension measurement: The surface tension of the water intrusion inhibitors for oil and gas reservoirs in different embodiments was tested. The surface tension was measured using a surface tensiometer at 80°C using the platinum ring method.

[0036] Gas phase permeability determination of porous media in core: (1) The core was placed in a high-temperature and high-pressure displacement device with saturated simulated formation water (mineralization of 250,000 mg / L) for gas phase permeability testing at 80℃ to obtain the initial permeability. (2) 1 PV (PV refers to pore volume) of reservoir water intrusion inhibitor was injected, aged at 180℃ for 48 h, and a second gas phase permeability test was conducted at 80℃ to obtain the permeability of the treated core.

[0037] Spontaneous core adsorption experiments were conducted at 180℃ to investigate the water intrusion prevention capabilities of different systems. The specific procedures were as follows: After weighing the core dry, the sides of the core were sealed with tape, allowing the bottom of the core to contact simulated formation water with a salinity of 250,000 mg / L. The changes in the mass of formation water spontaneously adsorbed by the core over time were recorded and analyzed. Subsequently, the core was vacuum-sealed, then saturated with a reservoir water intrusion inhibitor, and finally dried. These steps were repeated to determine the change in core mass with spontaneous adsorption time. The water intrusion prevention capabilities of different systems were quantitatively evaluated by measuring the changes in spontaneous adsorption time and core water saturation.

[0038] Erosion resistance test: The prepared reservoir water intrusion inhibitor was diluted with 250,000 mg / L simulated formation water to form a 0.3 wt% water intrusion inhibitor solution. 1 PV (PV refers to pore volume) of the water intrusion inhibitor solution was injected, aged at 180℃ for 48 h, and gas permeability tests were conducted to obtain the initial core permeability. Subsequently, 50 PV of 250,000 mg / L simulated formation water was injected for erosion, and a second gas permeability test was conducted to obtain the treated core permeability.

[0039] Example 1

[0040] Modifying agent: Composed of a fluorocarbon surfactant and a hydrophilic siloxane coupling agent. The fluorocarbon surfactant is perfluorooctylsulfonamide (CAS: 754-91-6, purchased from Shanghai Yafu Chemical Technology Co., Ltd.). The hydrophilic siloxane coupling agent is 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane (CAS: 2530-83-8, purchased from Hangzhou Dadi Chemical Co., Ltd.). The mass ratio of perfluorooctylsulfonamide to 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane is 1.7:1.

[0041] The reservoir water intrusion inhibitor provided in this embodiment comprises the following components by weight percentage: 0.5 wt% modified treatment agent, 0.5 wt% hydrophilic nano-SiO2 (purchased from Jingjiang Tonggao Chemical Co., Ltd.), and the remainder being methanol.

[0042] The surface tension (surface tension measurement), core permeability before and after treatment (gas phase permeability recovery measurement), core water absorption before and after treatment (core self-absorption experiment), and core permeability before and after scouring (scouring resistance experiment) were measured. The results are shown in Table 1.

[0043] The contact angle of the gas-liquid-solid three phases was measured to be 92°. Figure 1 .

[0044] Example 2

[0045] The difference from Example 1 is that only 0.5% of the modifier and the remainder methanol are used.

[0046] Modifying agent: Composed of a fluorocarbon surfactant and a hydrophilic siloxane coupling agent. The fluorocarbon surfactant is perfluorooctylsulfonamide (CAS: 754-91-6, purchased from Shanghai Yafu Chemical Technology Co., Ltd.). The hydrophilic siloxane coupling agent is 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane (CAS: 2530-83-8, purchased from Hangzhou Dadi Chemical Co., Ltd.). The mass ratio of perfluorooctylsulfonamide to 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane is 1.4:1.

[0047] The reservoir water intrusion inhibitor provided in this embodiment consists of 0.5 wt% of a modifying agent and the remainder methanol.

[0048] The surface tension (surface tension measurement), core permeability before and after treatment (gas phase permeability recovery measurement), core water absorption before and after treatment (core self-absorption experiment), and core permeability before and after scouring (scouring resistance experiment) were measured. The results are shown in Table 1.

[0049] The contact angle between the gas, liquid, and solid phases was measured to be 81°. Figure 2 .

[0050] Example 3

[0051] The difference from Example 1 is that the mass fractions of the modifier and nano-SiO2 are changed to 1.0% and 0.5%, respectively.

[0052] Modifying agent: Composed of a fluorocarbon surfactant and a hydrophilic siloxane coupling agent. The fluorocarbon surfactant is perfluorooctylsulfonamide (CAS: 754-91-6, purchased from Shanghai Yafu Chemical Technology Co., Ltd.). The hydrophilic siloxane coupling agent is 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane (CAS: 2530-83-8, purchased from Hangzhou Dadi Chemical Co., Ltd.). The mass ratio of perfluorooctylsulfonamide to 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane is 1:1.

[0053] The reservoir water intrusion inhibitor provided in this embodiment comprises the following components by weight percentage: 1.0 wt% modified treatment agent, 0.5 wt% hydrophilic nano-SiO2 (purchased from Jingjiang Tonggao Chemical Co., Ltd.), and the remainder being methanol.

[0054] The surface tension (surface tension measurement), core permeability before and after treatment (gas phase permeability recovery measurement), core water absorption before and after treatment (core self-absorption experiment), and core permeability before and after scouring (scouring resistance experiment) were measured. The results are shown in Table 1.

[0055] The contact angle between the gas, liquid, and solid phases was measured to be 134°. Figure 3 .

[0056] Example 4

[0057] The difference from Example 1 is that the mass fractions of the modifier and nano-SiO2 are changed to 2.0% and 0.5%, respectively.

[0058] Modifying agent: Composed of a fluorocarbon surfactant and a hydrophilic siloxane coupling agent. The fluorocarbon surfactant is perfluorooctylsulfonamide (CAS: 754-91-6, purchased from Shanghai Yafu Chemical Technology Co., Ltd.). The hydrophilic siloxane coupling agent is 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane (CAS: 2530-83-8, purchased from Hangzhou Dadi Chemical Co., Ltd.). The mass ratio of perfluorooctylsulfonamide to 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane is 1.5:1.

[0059] This embodiment provides a water intrusion inhibitor for oil and gas reservoirs, comprising the following components by weight percentage: 2.0 wt% modified treatment agent, 0.5 wt% hydrophilic nano-SiO2 (purchased from Jingjiang Tonggao Chemical Co., Ltd.), and the remainder being methanol.

[0060] The surface tension (surface tension measurement), core permeability before and after treatment (gas phase permeability recovery measurement), core water absorption before and after treatment (core self-absorption experiment), and core permeability before and after scouring (scouring resistance experiment) were measured. The results are shown in Table 1.

[0061] The contact angle between the gas, liquid, and solid phases was measured to be 152°. Figure 4 .

[0062] Example 5

[0063] The difference from Example 1 is that no modifying agent is used; only hydrophilic nano-SiO2 with a mass fraction of 0.5% is used.

[0064] This embodiment provides a water intrusion inhibitor for oil and gas reservoirs, comprising the following components by weight percentage: 0.5 wt% modifier and the balance methanol.

[0065] The surface tension (surface tension measurement), core permeability before and after treatment (gas phase permeability recovery measurement), core water absorption before and after treatment (core self-absorption experiment), and core permeability before and after scouring (scouring resistance experiment) were measured. The results are shown in Table 1.

[0066] The contact angle between the gas, liquid, and solid phases was measured to be 12°. Figure 5 .

[0067] Example 6

[0068] The difference from Example 1 is that the mass fractions of the modifier and nano-SiO2 are changed to 2.0% and 0.1%, respectively.

[0069] Surface tension (surface tension measurement), core permeability before and after treatment (gas phase permeability recovery measurement), core water absorption before and after treatment (core self-absorption experiment), and core permeability before and after scouring (scouring resistance experiment) were measured. The results are shown in Figure 1.

[0070] The contact angle between the gas, liquid, and solid phases was measured to be 137°. Figure 6 .

[0071] Example 7

[0072] This embodiment provides a water invasion inhibitor for oil and gas reservoirs, comprising the following components by mass percentage: 2.0 wt% modified treatment agent, 0.2 wt% hydrophilic nano-SiO2, and the remainder being alcohol.

[0073] It is composed of a fluorocarbon surfactant and a hydrophilic siloxane coupling agent. The fluorocarbon surfactant is perfluorooctylsulfonamide (CAS: 754-91-6, purchased from Shanghai Yafu Chemical Technology Co., Ltd.). The hydrophilic siloxane coupling agent is 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane (CAS: 2530-83-8, purchased from Hangzhou Dadi Chemical Co., Ltd.). The mass ratio of perfluorooctylsulfonamide to 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane is 1.7:1.

[0074] The reservoir water intrusion inhibitor provided in this embodiment comprises the following components by weight percentage: 2.0 wt% modified treatment agent, 0.2 wt% hydrophilic nano-SiO2 (purchased from Jingjiang Tonggao Chemical Co., Ltd.), and the remainder being methanol.

[0075] Surface tension (surface tension measurement), core permeability before and after treatment (gas phase permeability recovery measurement), core water absorption before and after treatment (core self-absorption experiment), and core permeability before and after scouring (scouring resistance experiment) were measured. The results are shown in Figure 1.

[0076] The contact angle between the gas, liquid, and solid phases was measured to be 141°. Figure 7 .

[0077] Example 8

[0078] The difference from Example 7 is that the mass fraction of nano-SiO2 used is changed to 0.3 wt%.

[0079] It is composed of a fluorocarbon surfactant and a hydrophilic siloxane coupling agent. The fluorocarbon surfactant is perfluorooctylsulfonamide (CAS: 754-91-6, purchased from Shanghai Yafu Chemical Technology Co., Ltd.). The hydrophilic siloxane coupling agent is 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane (CAS: 2530-83-8, purchased from Hangzhou Dadi Chemical Co., Ltd.). The mass ratio of perfluorooctylsulfonamide to 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane is 1.7:1.

[0080] The reservoir water intrusion inhibitor provided in this embodiment comprises the following components by weight percentage: 2.0 wt% modified treatment agent, 0.3 wt% hydrophilic nano-SiO2 (purchased from Jingjiang Tonggao Chemical Co., Ltd.), and the remainder being methanol.

[0081] The surface tension (surface tension measurement), core permeability before and after treatment (gas phase permeability recovery measurement), core water absorption before and after treatment (core self-absorption experiment), and core permeability before and after scouring (scouring resistance experiment) were measured. The results are shown in Table 1.

[0082] The contact angle of the gas-liquid-solid three phases was measured to be 148°. Figure 8 .

[0083] Table 1

[0084]

[0085] While the present invention has been described with reference to specific embodiments, those skilled in the art will understand that various changes can be made without departing from the true spirit and scope of the invention. Furthermore, numerous modifications can be made to the subject, spirit, and scope of the invention to suit specific situations, materials, material compositions, and methods. All such modifications are included within the scope of the claims of the present invention.

Claims

1. An oil and gas reservoir water invasion inhibitor comprising a modified treatment agent, nano-silica and an alcohol.

2. The inhibitor of claim 1, wherein The modified treatment agent comprises a fluorocarbon surfactant and a hydrophilic siloxane coupling agent.

3. The inhibitor of claim 2, wherein The fluorocarbon surfactant comprises perfluorooctyl sulfonamide; and / or the hydrophilic siloxane coupling agent comprises 3-(2,3-epoxypropoxy)aminopropyltrimethoxysilane.

4. The inhibitor of claim 2, wherein The mass ratio of the fluorocarbon surfactant to the hydrophilic siloxane coupling agent is (1.4-1.7):

1.

5. The inhibitor of claim 1, wherein The alcohol is methanol and / or ethanol.

6. The inhibitor of claim 1, wherein The alcohol is a mixture of methanol and ethanol in a volume ratio of 1:

1.

7. The inhibitor of claim 1, wherein The nano-silica is hydrophilic nano-silica.

8. The inhibitor of claim 1, wherein The content of the modified treatment agent is 1% to 3% and the content of the nano-silica is 0.1% to 0.5%, based on 100% of the total mass of the inhibitor.

9. The inhibitor of claim 1, wherein The content of the modified treatment agent is 2% to 2.5% and the content of the nano-silica is 0.1% to 0.3%, based on 100% of the total mass of the inhibitor.

10. Use of the inhibitor according to any one of claims 1 to 9 in the water invasion of an oil and gas reservoir, in particular in the inhibition of water invasion in a high-temperature and high-salinity oil and gas reservoir.

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